The present invention relates to polymeric modification. More particularly, the present invention relates to the modification of solid polymers containing unsaturation by reaction with thiocyano- or isothiocyanogenerating reactants so as to cause thiocyano or isothiocyano addition only on the available surface of such polymers.
In U.S. Pat. No. 3,607,536 to R. A. Bragole, a method for bonding resinous substrates such as polyethylene by radiation induced isocyanate modification thereof is disclosed. After being so modified, the resinous substrate may be easily bonded by adhesives capable of bonding to polyurethane or rubber surfaces.
In U.S. Pat. No. 2,781,331 diene polymers are thiocyanated by reaction with thiocyanogen. By reducing the level of unsaturation through hydrogenation the amount of thiocyanate moieties added to the polymer may be controlled. Similar techniques for thiocyanating ethylenically unsaturated polymers are disclosed in U.S. Pat. No. 2,287,774 and U.S. Pat. No. 3,867,360.
Previously known thiocyanation processes have resulted in addition of functionality throughout the polymer and consequent excessive use of thiocyanating agent. In addition, previously known processes have involved solution treatment of polymers making the procedure unsuited for use with solid polymeric objects such as molded materials. The procedure has been likewise unsuited for use with normally fully saturated polymers such as polyolefins.